The invention relates to a surgery microscope with a front lens thereof having at least one displaceable element and through which light beams are passed in addition to observation beams.
In microsurgical operations, it is often necessary to focus the surgery microscope onto a higher or lower plane in the observation field. If the optical axis of the microscope was not parallel to one of the displacement or support axes of the microscope mounting or the operating table, although a displacement of the entire microscope or the patient along one of these axes would bring about a focusing, it would lead to a lateral drift of the observed object in the field of vision.
This disadvantage is already obviated in known surgery microscopes with continuously variable working distance. A surgery microscope is known with a displaceable front lens having a continuously variable working distance (DAS No. 1,220,630). In addition, a surgery microscope has been proposed with a two-element front lens with variable focal lengths (DOS No. 2,439,820).
If in a surgery microscope with displaceable front lens or with a variable lens focal distance, the path of the illumination rays is passed through the front lens alongside the path of the observation rays, there are numerous reflections on the individual surfaces of the lens components and they are displaced in a substantially uncontrollable manner on displacing the lens or its displaceable element. Even in the case of a top quality dereflection or blooming of the surfaces disturbing light source reflections still penetrate the adjacent path of the observation rays.